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Патент USA US3089982

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May 14, 1963
Filed July 14, 1960
FIG. 2.
W90 sg 3
United States
Patented May 14, 1963
length, to provide the desired region of decreased tempera
ture within the lamp. The base attached to the end of
Orange, N.J., assignors to Westinghouse Electric Corpo
ration, East Pittsburgh, Pa., a corporation of Pennsyl
the lamp having the aforesaid cooling tube is proportion
ately elongated and used to protectively enclose the tube
in addition to its usual function of connecting the lamp
Daniel A. Larson, Cedar Grove, and Peter J. Walsh, East
to its socket.
Filed July 14, 1960, Ser. No. 42,796
9 Claims. (Cl. 313-34)
In addition, the base is preferably constructed to insu
late the cooling tube from the heat radiating from the ad
jacent end of the envelope and to maintain a ?ow of air
This invention relates to electric discharge devices and, 10 past the tube so as to lower its operating temperature as
more particularly, to a highly-loaded ?uorescent lamp
much as possible and thus keep the length of both the
and means for controlling the mercury-vapor pressure
tube and base to a minimum.
thereof during operation.
A better understanding of the invention will be ob
As is well known, the efficiency and light output of a
tained by referring to the accompanying drawing wherein:
?uorescent lamp is dependent upon the mercury-vapor 15
FIG. 1 is an elevational view of a highly-loaded ?uores
pressure within the lamp. It is also well known that
cent lamp which incorporates the improved vapor pres
optimum e?ciency and light output occurs when the mer
sure control means and base of this invention, the central
cury-vapor pressure is maintained within the range of
part of the lamp being omitted for convenience of illus
about 6 to 10 microns and that this pressure can be ob
tained by providing a region within the lamp that has an 20
FIG. 2 is an enlarged fragmentary view of the lamp
operating temperature between about 40° to 45° C.
shown ‘in FIG. 1, mainly in section, showing the cooling
Conventional ?uorescent lamps having a loading of
tube and base construction of this invention in greater
around 10 watts per foot of lamp length present no diffi
culty in this regard since substantial portions of the bulb
FIG. 3 is a plan view of the end of the lamp shown in
wall inherently operate in the aforesaid temperature range. 25 FIG. 2 that has the cooling tube and modi?ed base in ac
However, in the so-called highly-loaded ?uorescent lamps
(that is, those which operate at loadings of 25 watts per
foot of lamp length and higher) more heat is generated
cordance with the invention;
FIG. 4 is a cross-sectional view through the basal end
of the lamp along the line IV-eIV of FIG. 2, in the di
within the gaseous discharge which, in turn, causes the
rection of the arrows;
envelope to operate at a much higher temperature. In 30
FIG. 5 is an exploded perspective view of the base mem:
order to avoid the resultant decrease in light output and
ber shown in the preceding ?gures; and
efficiency it is accordingly necessary to provide a cool
FIG. 6 is a cross-sectional view corresponding to FIG.
region or so-called cooling chamber within such highly
4 but showing another type of base according to the in
loaded lamps that will maintain the mercury-vapor pres
sure at the desired value.
Various means have heretofore been employed to pro
vide such cooling chambers. Among these have been
While the present invention maybe advantageously em
ployed in various types of vapor discharge devices that
require means for controlling the vapor pressure during
operation, it is especially adapted for use in conjunction
with highly-loaded ?uorescent lamps and accordingly has
the use of a tubulation that projects radially outward
from the center of the envelope, and the use of longer
stem mounts at each end of the lamp which mounts are 40 been so illustrated and will be so described.
?tted with heat shields that separate the ends of the en
In FIG. 1 there is shown a highly-loaded ?uorescent
velope from the cathodes to form end chambers. How
lamp 10 comprising a sealed tubular and radiation-trans
ever, the aforesaid structures leave much to be desired
mitting envelope 12 having bases 13 and 14 attached to
insofar as the radially extending tubulation is susceptible
each of its ends. Each base is provided with a protrud
to breakage, produces strains in the glass and detracts 45 ing elongated boss 15 and 16 of insulating material which
from the appearance of the lamp; whereas the elongated
bosses are appropriately contoured, as is well known, 'to
cooling chambers at each end of the envelope shorten
accommodate recessed contacts for connecting the lamp
the arc length and produce dark ends. In addition, both
to a socket and an electrical power source. As is shown
of these designs require the use of additional parts and
more particularly in FIG. 2, reentrant type stems 19 and
assembly operations which increase the manufacturing
20 are sealed to the ends of the envelope 12 and support
cost of the lamp.
the usual activated electrodes 21 and 22, respectively, in
With the foregoing in mind it is the general object of
operative relationship Within the envelope. The inner
this invention to provide an improved metallic-vapor dis
surface of the envelope is coated with the customary UV
charge device that will operate at a preselected vapor
responsive phosphor 13 and the envelope is charged with
pressure and can ‘be easily and inexpensively fabricated. 55 a predetermined quantity of mercury 32 and a suitable
Another and more speci?c object is the provision of a
starting gas such as neon or argon, or a mixture thereof,
highly-loaded ?uorescent lamp that will operate at opti
in the usual manner.
mum e?iciency and is of rugged and simple construction.
In accordance with this invention the axially-extending
Still another object of this invention is the provision of
exhaust tribulation that is normally provided on one of
an improved vapor pressure control means and accom
the stem assemblies, the stem 20‘ as illustrated in FIG. 2,
modating base member for a highly-loaded ?uorescent
and which communicates with the interior of the envelope
lamp wherein certain parts serve a dual purpose and the
12 through an aperture 33 in said stem, is used as the cool
total number of parts required are accordingly kept to a
ing chamber. This is accomplished by tipping-oif the
aforesaid exhaust tubulation at a point much further from
The foregoing objects, and others which will become 65 the end of the envelope than heretofore thereby to pro
apparent to those skilled in the art, are achieved in accord
ance with this invention by utilizing as the cooling means
the axially-extending exhaust tube that is normally pro
vided on one of the electrode mount assemblies sealed to
vide a cooling tube 30 of such length and diameter that
at least a part thereof has a lower operating temperature
than the envelope proper. More speci?cally, the length
and diameter of the cooling tube 30‘ is such that itpro
the ends of the bulb. The exhaust tube is merely tipped 70 vides a cool region within the lamp that has an operating
o?? at a point such that it is considerably longer than here
temperature within the desired range of about 40° to
tofore and is thus adapted, by virtue of its increased
45° C. As a result, the mercury 32 will tend to con-'
dense within the cooling tube 30 (as shown in FIG. 2).
thereby maintaining the mercury-vapor pressure within
the prescribed limits for optimum e?iciency and light out
put without the use of any additional tubulation or seal
ing operations.
As shown in FIG. 1, the base 13 is of the usual shal
low construction whereas the base 14 is elongated so as
to protectively enclose but remain spaced from the cool
ing tube 30. A heat barrier or shield 34 of suitable low
heat-conductive material such as plastic is desirably pro
vided inside the base to insulate the cooling tube 30 from
the heat radiated from the adjacent end of the envel
ope 12.
As will be understood, the exact diameter and length of
the cooling tube 30 will vary considerably depending
upon the wattage rating of the lamp, the type of metal
vapor employed therein, etc. As a speci?c example, it p
C1 has been found that a highly-loaded 100 watt T12 ?uores
cent lamp approximately 4 foot in length and containing
a ?ll gas of 80% neon-20% argon at 2 mm. pressure
and mercury, operated at its rated wattage and et?ciency
when provided with a cooling tube having an outside
diameter of approximately 3/16”, a wall thickness of ap
proximately 1 mm, and which extended 1" beyond the
sealed lip of the envelope. Arc voltage measurements
taken while the lamp operated at rated watts and e?i
ciency showed that a vapor pressure equivalent to a tem
As shown more particularly in FIGS. 2, 3 and 5, the
base 14 consists of a cylindrically hollow shell, preferably 15 perature of about 43° C., or approximately in the middle
of molded plastic, that is open at one end and partly closed
at the other end by an end Wall 17 and the aforesaid boss
16, which boss has a central opening 26 and lead wire
passages therethrough. Cavities 28 in the outer face of
the boss 16 connect the central opening 26 with the afore
said passages and provide recesses for either the lamp
contacts or for the lead wires 23 and 24 that are sealed
of the permissible range, was maintained with this par
ticular combination of lamp and tube.
‘By using a cooling tube as above described rather than
cooling chambers at the ends of the lamp, lamps have
been made which operate at the same wattage and have
the same electrode spacing as “end cooled” lamps but
which are 21/2" shorter in overall length. If the arc
length of the lamp having the cooling tube were in
through the stem 20, depending upon the type of base and
creased by this same amount so as to provide a lamp hav
terminal construction employed. The outer ends of the
the same overall length, the wattage and light output
lead wires may be ?attened and bent into the aforesaid
thereof would be increased by approximately 61/2 %.
recess cavities and opening and thus used as the lamp
The aperture 33 is approximately the diameter of the
terminals so as to provide the desired recessed contact
tube 30. If desired, two heat shields may be
structure at minimum cost. This type base and terminal
used in each base to provide an insulating air space and
construction is disclosed and claimed in copending appli
both ends of the lamp 10 may be provided with cooling
cation Serial No. 784,488, W. Pechy, ?led January 2,
This latter feature will decrease the time required
1959, and assigned to the assignee of the present inven
for the mercury-vapor pressure to reach its equilibrium
A circumferential shoulder or abutment 36 (see FIGS.
It will be recognized from the foregoing that the ob
2 and 5) on the inner surface of the base shell proximate
jects of the invention have been achieved by providing an
the open end thereof serves as a seat for the heat shield
improved highly-loaded ?uorescent lamp and vapor pres
34 and divides the shell into a lamp-receiving portion and
sure control means therefor. By utilizing the exhaust
an elongated intermediate portion along a plane trans
verse to the base axis. The heat shield 34 is of circular
con?guration and dimensioned and keyed so as to be
tube as the cooling chamber and one of the base mem
bers as a protective enclosure for the elongated tube, a
registrably insertable into the base against the abutment 40 lamp structure is provided which is not only exceptionally
rugged but which requires a minimum of parts and labor
34. When thus disposed, it partitions the outwardly dis
for its manufacture.
posed portion of the base 14 from the envelope 21 and
While several embodiments have been illustrated and
together with said portion forms a compartment or en
it is to be understood that various modi?ca
closure A for the cooling tube 30. The aforesaid tube and
tions in the con?guration and organization of parts may
lead wires 23 and 24 axially project through an elongated
be made without departing from the spirit and scope of
opening 35 in the shield 34 and therebeyond into centrally
the invention.
located position within the enclosure A, with the leads
We claim:
passing through and into the boss 16 as shown.
1. A metallic-vapor discharge device of the type de~
Vent openings 18 are desirably provided in the inter
mediate portion of the base shell and are preferably dis 50 signed to be operated under such conditions that the me
tallic-vapor pressure normally would be higher than that
posed in the same plane as the lead wires 23 and 24, as
required for optimum efficiency, comprising a sealed en
shown in FIG. 4, and the recess cavities 28 so as to be
velope containing spaced electrodes between Which a
located above and below the cooling tube tube 30 when
gaseous discharge occurs during the operation of said de
the boss 16 is vertically disposed. In this manner a ther
vice, a tubulation integral with and extending from one
mally induced current of air will ?ow past the cooling
end of said envelope, and a base attached to said one end
tube 30 when the lamp 10 is operated with the boss 16
in such position. The vents also permit radiation from
the warmer components in the enclosure A to escape.
‘If desired, groups of vent openings 18a and 38 circum
of said envelope protectively enclosing but spaced from
said tubulation, said base having an envelope-receiving
portion and an intermediate vented portion, the outer end
ferentially spaced approximately 90° from each other 60 of said tubulation being closed and the inner end thereof
being open and communicating with the interior of said
with one pair of diametrically opposed openings dis
envelope, said tubulation extending a considerable dis
posed in approximately the same plane as the lead wires
tance beyond the end of said envelope and into the inter
and recess cavities may be provided, as shown in the al
mediate vented portion of said base, the length and diam~
ternative embodiment illustrated in FIG. 6, to permit the
desired convection cooling to occur regardless of whether 65 eter of said tubulation being such that at least a part there
of has a lower operating temperature than said envelope
the lamp 10 is operated with the boss 16 disposed in a
and thereby provides a cool region within said device
vertical or horizontal position.
that reduces the metallic~vapor pressure and maintains it
In order that the desired regulation of the mercury
at approximately the desired value.
vapor pressure may be obtained with a cooling tube 30
and base 14 of the shortest possible length, the surface of 70 2. A metallic-vapor discharge device as set forth in
claim 1 wherein said base includes a transverse shield
the heat shield 34 facing the envelope 12 is preferably
that insulates the closed end segment of said tubulation
coated with a material 37 (see FIGS. 1 and 5), such as
from the heat emanating from the adjoining end of said
aluminum or the like, that is highly re?ective to infrared
radiation so that the heat energy emanating from the elec~
3. A mercury-vapor discharge lamp of the type de
trade 20 will be re?ected back into the lamp.
signed to be operated under such conditions that the mer
cury-vapor pressure normally would be higher than that
required for optimum light output, comprising a sealed
ing chamber for and maintains the mercury-vapor pres
sure at approximately the value required for optimum
tubular radiation-transmitting envelope containing a pair
light output.
of spaced electrodes at least one of which is supported by
6. The combination of a base, heat shield and vapor
pressure regulating tube in a highly-loaded fluorescent
lamp as set forth in claim 5 wherein, said stem is of the
reentrant type, and said base is provided with recessed
contacts for connecting said lamp with an electrical power
a stem sealed to one end of said envelope, a vitreous tube
hermetically joined to said stem and extending axially
outward therefrom, a vented base attached to said one
end of said envelope protectively enclosing but spaced
said envelope, whereby said vitreous tube serves as a cool
from said tube, and a heat shield of low heat-conductive 10 supply.
material within said base located proximate the end of
7. A base for an electric discharge lamp comprising, a
said envelope transversely of the lamp axis, said tube pro
cylindrically hollow shell that is open at one end and
jecting through an opening in said heat shield and ex
partly closed at the other, a circumferential abutment on
tending a substantial distance therebeyond, the outer end
the inner surface of said shell located proximate the open
of said tube being sealed oh? and the inner end thereof 15 end thereof and dividing said shell into a lamp-receiving
communicating with the interior of said envelope through
portion and an elongated intermediate portion along a
an aperture in said stem, said tube having a length and
plane transverse to the axis, an apertured circular heat
diameter such that at least a part thereof has a lower
shield of low heat-conductive material insertable into the
operating temperature than said envelope and thereby
lamp-receiving portion of said shell against the aforesaid
provides a cool region Within said lamp that reduces the
abutment, and a pair of opposed recess cavities in the end
mercury-vapor pressure and maintains it at approximately
of said shell opposite the open end thereof for accom
the desired value.
modating the terminals of said lamp, said intermediate
4. A mercury-vapor discharge lamp as set forth in
portion of said shell having at least two vent openings
claim 3 wherein said base has vent openings located above
therein located in approximately the same plane as said
and below said tube when said lamp is oriented in ‘the po 25 opposed recess cavities.
ition in which it normally is operated.
8. A lamp base as set forth in claim 7 wherein at least
5. In combination with a highly-loaded ?uorescent lamp
one side of said heat shield is coated with a material that
that includes a sealed tubular radiation-transmitting enve
re?ects infrared radiation.
lope Iwhich contains a charge of mercury and has a stem at
9. A lamp base as set forth in claim 7 wherein said
one end from which a pair of lead wires extend, a vitreous 30 intermediate portion of said shell has a plurality of vent
tube fused to said stem and communicating with the in
openings therein circuniferentially spaced approximately
terior of said envelope through an aperture in said stern,
90° from each other with one pair of diametrically op
a base attached to the said end of said envelope, and a
posed openings disposed in approximately the same plane
heat shield in said base partitioning the outwardly dis
as said recess cavities.
posed portion thereof from said envelope, said vitreous 35
tube and lead wires projecting through an opening in said
heat shield and into the enclosure formed 1by said heat
shield and said outwardly disposed portion of said base,
a plurality of openings in said base located to permit the
circulation of air through said enclosure and past the 40
References Cited in the ?le of this patent
Yoder ______________ __ Dec. 26, 1950
{Fox ________________ __ Oct. 25, 1960
Great Britain ________ __ Oct. 16, 1957
Germany ____________ __ Dec. 15, 1955
portion of said vitreous tube disposed therewithin, the
outer end of said vitreous tube being sealed off and said
tube having a length and diameter such that at least a
portion thereof has a lower operating temperature than
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